Gastrointestinal System >
Clostridium Difficile Infection (CDI)

Highly infectious spore-forming and toxin-producing gram positive anaerobic bacillus, which causes an important hospital-acquired infection responsible for 20-30% of antibiotic-associated colitis”

Risk Factors
  • Antibiotic use (within the last 2 weeks)
    • Especially fluoroquinolones, clindamycin and broad-spectrum penicillins and cephalosporins.
    • Multiple antibiotics or long duration of antibiotics also increases risk.
  • Age ≥65
  • Hospitalisation
  • Severe underlying comorbidities
  • Gastric acid suppression (e.g. PPI medication)
  • Enteral feeding GI surgery
  • Obesity
  • Chemotherapy
Aetiology
  • There are toxigenic (exotoxin producing) and non-toxigenic (cannot produce exotoxins) strains of C. difficile.  
  • Non-toxigenic strains are found in around 2% of healthy adults as commensals in the bowel.
  • Only toxigenic strains cause disease.  
  • C. difficile spreads via spores released from asymptomatic or symptomatic carriers of the pathogen.
    • These spores are highly infectious and resistant to acid, heat and antibiotics
Pathophysiology
  1. Antibiotics disrupt normal colonic microbiota, which usually compete with C. difficile.
  2. Toxigenic strains of C difficile are resistant to antibiotics and are able to multiply and release toxins pseudomembranous colitis (appearance on endoscopy).
  3. Toxins cause colonic inflammation, intestinal fluid secretion, mucosal damage, neutrophil activation
Clinical Presentation
  • Watery diarrhoea (≥3 loose bowel motions within 24 hours)
  • Abdominal pain
  • Nausea & fever.
  • Mild:
    • No systemic features,
    • ≤3 bowel motions per day
    • Normal WCC
  • Moderate:
    • 3-5 bowel motions
    • Raised WCC
  • Severe:
    • WCC > 15×109
    • Raised creatinine
    • Fever >38.5 or evidence of severe colitis.
  • Fulminant:
    • Hypotension
    • Tachycardia
    • Ileus (partial or complete)
    • Toxic megacolon
    • CT evidence of severe disease
Investigations
  • Bloods:
    • WCC (↑)
    • Routine bloods (FBC, U&Es, LFTs)
    • Blood cultures
    • VBG (lactate)
  • Imaging:
    • Abdominal X-ray
    • CT abdomen pelvis (if severe disease)
    • Flexible sigmoidoscopy (usually avoided)
  • Special:
    • C. difficile toxin in stool – NAAT (nucleic acid amplification testing
    • EIA (enzyme immunoassay e.g. enzyme glutamate dehydrogenase))
    • C. difficile antigen in stool (only shows exposure, not active infection)
Management
  • SIGHT:
    • Suspect
    • Isolate within 2 hours
    • Gloves and aprons
    • Hand washing with soap and water
    • Test immediately.
  • Correct fluid losses.
  • Stop current antibiotics.
  • Mild/moderate:
    • Metronidazole PO for 10-14 days
  • Severe:
    • Vancomycin PO for 10-14 days.
    • Switch to fidaxomicin or add metronidazole if no improvement at 7 days.
  • Fulminant:
    • Vancomycin PO and metronidazole PO.
    • IV metronidazole if ileus.
  • Recurrent CDI:
    • Faecal microbiota transplantation (FMT)
Complications
  • Hypotension,
  • Ileus
  • Toxic megacolon (>6cm)
  • Bowel perforation
  • Shock

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